1. Field of the Invention
The present invention relates, in general, to electrical watthour meters and, more specifically to watthour meter socket adapters.
2. Description of the Art
In the electric utility industry, watthour meters are commonly employed to measure electrical power consumption at a residential or commercial building establishment. A cabinet is typically mounted on an outside wall of the residence or building and contains a meter socket having pairs of line and load terminals which are connected to electric power line conductors extending from the utility power network and electric load conductors connected to the residential or building establishment power distribution network. The line and load terminals are connected to blade terminals extending outward from the base of a watthour meter to complete an electric circuit through the watthour meter between the line and load terminals mounted in the socket for the measurement of electrical power consumption.
A "B" type watthour meter is provided with a Plurality of rigid, generally tubular conductors which extend downward and outward from the meter housing and are insertable into and fixedly attachable to the terminals in the watthour meter socket.
S-type, socket-type, plug-in watthour meters have replaced older A base bottom connected meters which were formed of a single piece housing in which the watthour meter was fixedly mounted along with compression terminals which provide connection to the utility power lines and the building load distribution network. An S-type watthour meter also has outwardly extending blade terminals. In order to mount such an "S" type meter in an S to B watthour meter socket, solid tubular conductors preformed to the desired shape were bolted directly to the watthour meter blade terminals as shown in FIG. 1. The outer ends of the tubular conductors were then inserted into circular or rectangular shaped openings in the watthour meter socket terminals and fastened in place to complete an electrical circuit with electric power line and load conductors which were also connected to the watthour meter socket terminals. Potential wires were then connected to the watthour meter and to terminals mounted on a plate attached to the tubular conductors.
The next advance in S to B type watthour meter construction was the mounting of the tubular conductors in a rigid frame as shown in FIG. 2. Stranded wire conductors were crimped at one end to the tubular conductors and then extended to a bolted connection with the appropriate blade terminals on the back of the watthour meter.
Both of these prior art S to B type watthour meter constructions require extensive labor to connect each individual conductor to the watthour meter and/or to crimped the stranded conductors to the tubular conductors. Additional labor was also necessary to attach the potential wires to the watthour meter and to the terminals on the frame.
Next, FIG. 3, depicts the next development of an S to B watthour meter adapter. A CT rated adapter, as shown, but the adapter could also have been constructed as a self-contained adapter. In this prior art construction, hollow tubular conductors were crimped to stranded wire conductors. The stranded wire conductors were in turn connected to jaw contacts fixedly mounted in a watthour meter socket adapter housing at standard mounting positions to receive the watthour meter blade terminals in a snap-in connection. Potential wires from potential jaw terminals mounted in the watthour meter socket adapter housing were run to disconnect links on the front of a terminal block formed on the socket adapter housing. The tubular conductors pass through bores machined in an insulating block made polyvinyl chloride and extend downward from the annular rim of the socket adapter. A ground connect pin is mounted by means of a bracket on a back plate attached to the socket adapter housing. The pin is connected by a conductor to the ground jaw of the socket adapter and receives a plug-in connector not shown, which is in turn connected to ground in the watthour meter socket.
However, as with the first two above-described prior art constructions, the S to B watthour meter socket adapter shown in FIG. 3 still had a high manufacturing cost due to the extensive labor required to connect each individual stranded wire conductor to a tubular conductor and to a jaw contact. Further, the stranded wire conductors provided only a limited current carrying capability. Special potential wires and extensive labor were also necessary to bring the potential wires out to the front of the terminal block to enable testing of the watthour meter. In addition, extra labor and cost are involved in mounting the ground pin externally from the adapter housing.
It is estimated that approximately one quarter million B type watthour meter sockets are currently in use. However, S to B watthour meters are no longer being made and the tooling for such S to B watthour meters no longer exists. Thus, while electric utilities are replacing S to B watthour meters, the utilities do not desire to replace the B-type watthour meter sockets due to the high cost of the sockets.
Thus, it would be desirable to provide an S to B watthour meter socket adapter which overcomes the above-described deficiencies in previously devised S to B watthour meter socket adapters. It would also be desirable to provide an S to B watthour meter socket adapter which has a higher current carrying capability than previously devised S to B type watthour meter socket adapters. It would also be desirable to provide an S to B watthour meter socket adapter which enables a watthour meter to be tested by standard meter test procedures without extensive labor or construction costs. Finally, it would be desirable to provide an S to B watthour meter socket adapter which has a lower manufacturing cost due to the complete construction and conductor connections of the watthour meter socket adapter by the socket adapter manufacturer.